I've used a variety of hiking poles over the years, getting progressively lighter with time and money!
My current poles are the Gossamer Gear Lightrek 4 poles at just a shade over 4 oz per pole, but as strong as the beefier poles (e.g. Leki, Komperdell or Black Diamond). The GG poles are the best pole ever, IMO. Since I use the poles for rhythm and stability...and for tent/tarp/shelter poles, lighter is better. YMMV but I think one of the "workout" benefits is that of more actively using your arms/shoulders to assume some of the weightbearing load as you climb/descend. Just hiking along level trails I will often just carry the poles in one hand since they don't offer a lot of benefit for that specific condition. Definitely a help on logs/rocks when stream crossing or navigating wet trail conditions.